1. Field of the Invention
The present invention relates to an ion implanter.
2. Description of the Related Art
In a semiconductor production process, a process of implanting ions into a semiconductor wafer (hereinafter sometimes referred to as “an ion implantation process”) is generally performed for the purpose of changing a conductive property, changing a crystal structure of the semiconductor, and the like. An apparatus used in the ion implantation process is called an ion implanter, and the ion implanter functions to generate ions in an ion source and accelerate the generated ions to generate an ion beam and functions to transport the ion beam to a vacuum processing chamber and irradiate the wafer in the processing chamber with the ion beam.
In the ion implanter, an ion source, an extraction electrode, a mass analysis magnet unit, a beam scanning unit, a beam collimating unit, an angular energy filter unit, a wafer processing chamber, and the like are arranged along a beamline, for example, and the ion implanter is configured to implant ions into a wafer which may be a semiconductor substrate. These units constituting the beamline control an ion beam with use of an electric field generated between electrodes to which voltage has been applied and/or a magnetic field generated by the magnet unit. For example, to control voltage to be applied between electrodes of a unit constituting the beamline, a high-output dedicated power supply and a low-output dedicated power supply are used in combination.
When the voltage to be applied between the electrodes of the unit constituting the beamline changes, an trajectory of the ion beam to be transported along the beamline and an incident angle to the wafer can change. When the trajectory of the ion beam and the incident angle to the wafer change, a state of interaction between the ion beam and the wafer may change, which may influence a processing result of ion implantation.